This is the most basic example of vertical scaling by transferring connections to workers, rather than sharing server sockets. It was presented at JSConf US 2012. With this you can create some interesting balancing algorithms that cluster would defer to internal/OS logic.
A good first project when working with this is to implement sticky sessions based upon connection.remoteAddress and/or connection.remotePort.
A good advanced project is to change from a TCP based balancer to a HTTP(S) one and balance based upon not just connection.remoteAddress etc. but also on the protocol and/or Host header.